I am newbie to the iPhone scene and its kinda confusing for me as I dont have the iPhone with me. Hope someone can help me out

Situation : My brother got a new iPhone 3GS last month. He has to travel to many countries due to his work. We thought we will unlock the iPhone so that he can use local SIM in those countries. But we weren't aware that the new iPhone 3GS cannot be unlocked yet.

The phone is still under 1 month return policy. As he cant wait till June for the unlock, thinking of this :